Method and apparatus for bleaching pulp



A. D. M'ERRILL METHOD AND APPARATUS PoR BLEACHING PULP June 9, 1925. 1,541,371

Filed Marsh 9, 1925 5 sheets-sheet 1 June 9, 1925. 1,541,371 A. D. MERRILL.

METHODND APPARATUS FOR BLEACHING PULP Filed March 9, 1925 3 Sheets-Sheet 2 H TTORNEY.

June 9, 1.925.

A. D. MERRILL METHOD AND APPARATUS FOR BLEACHING PULP Filed March 9, 1925 3 Sheets-Sheet 5 TTORNEY Cil Patented June 9, 19215. K

UNITED STATE PA-TENT OFFICE',

ALBERT D. MRRILL, 0F WATERTOWN, NEW YORK, ASSIGNOR T0 THE STEBINS EN- GINEERrNGa MFG. oo., o'r WATERTOWN, NEW YORK, A conPoaA'rIoN oF NEW YORK.

'METHOD AND APPARATUS FOR BLEACHING- PULP.

Application mea March'- 9, 1925. serial No. 14,102.

To all whom t may concern:

Be it known that I, ALBERT I). Mannini., a citizen of the United States, residing at the city of Watertown, in the county of Jefferson and State of New Iorlr, have invented certain new and useful Improvements 1n Methods vand Apparatus for Bleaching Pulp,-

ofy which the following is a specification.

The object of my invention is to bleach cellulose and other paper libres, by method and apparatus which will bleach all the fibres evenly and uniformly by using a minimum amount of bleaching fluid, a less amount 'of steam, maintaining a quick operation, thus saving time, and operating upon a dense mass of pulp, approximately inl plastic mass; all the bleached pulp delivered being of a uniform standard texture, each fibre having strength and vitality.

' My method and apparatus can be employed as an independent batch system or as a continuous system.

The salient' feature of my system enables me to move the pulp as a dense mass upwardly in a vertical line, allowing the bleaching liquor to thoroughly penetrate and bleach the mass uniformly, thus bleach- -ing all the fibres and each libre to the desired bleaching effect. y

The various features of my invention and their advantages willreadily become apparent from reading' the following specification.

In the accompanying drawing forming part of this specification:

Fig. 1, 'is a longitudinal section on the line 1 1 of Fig. 2,

Fig. 2, is a plan view of the appara-tus,

Fig. 3, is a` plan View of the lower plate or basin only,

Fig. 4, is an enlarged section of the impeller casing and. the lower plate or basin, taken on the line 1-1 ofFig. 2,. and

Fig. .5',jis a section taken on line 5 5 of Fig. 4.

The apparatus for carrying my method into operation consists of an outer cylinder 1.- pr'eferably made of concrete and usually linedon its inner surface in an approved' in which end I place the lower plate or basin 4, having a .curved rounded out trough shape, said basin carrying vanes 5, radiating outwardly from its center 6, and are preferably shaped as shown in Fig. 3, they may be made separately or integral with the basin 4.. I may u se as many vanes as I- desire and find practical.

not movable and I may use them as found suitable.

On the basin 4, I support an impeller casing 7, through medium of the-legs 8, which rest in the recesses 9 in the basin 4.

On the inside of this casing 7 I provide the diagonal spira-Hy inclined vanes 10', there being three in the present instance, although I may use as many as found practical under varying conditions. p

At one side of the impeller casing 7, I provide an air duct or passage 12, which passes through one of the legs 8 as shown in Fig. 4, then passes through the basin 2 at the point 13, andthen through the concrete base at 15, and at the top of the impeller casing this air passage is formed as an annular compartment, and said compartment is provided with small vents as 17. through which the air can reach the interior and mix with the pulpI and lbleaclllingA Huid.

Ony the top of the impeller casing 7' and connected thereto in any desirable way, I

' provide an uptake 18 which flares upwardcylinder or tank;

At the top of the impeller casing I also lThe basin 4 and its vanes are preferably y provide a number of small guide vanes 20 which assist in a straight-upward travel of the pulp and liquor as it leaves the iml peller casing.

' 'The impeller is marked 21, and is of any approved form, however, being shown spiral, the impeller preferably cast with a hub 22, similar to the hubof a pulley, and it is mounted on the shaft 23, which extends downwardly through the basin 4 vat its center 6, at which point I provide a stuifing box and gland 24,.the shaft then continuing on down to its lower bearing 25.

`On the shaft 23, I mountat its lower extremity, a'large gear 26 which is revolved by a'drive gear 27 to which motion is imparted in any suitable way, which shaft 23 rotates or revolves the impeller, or this 1mpeller shaft may be connected lto a speed ransformer of any suitable or desirable deg t the lower part of the cylinder 1, and through the concrete, I pass pipes as 28, through which water is admitted to partially dilute` the pulp so that it can be dumped, for which purpose I provide a dump valve 29, operated by bevel gear 30, turning the gear shaft 31 lthrough medium of turnv rod 32 extending up to the hand turning wheel 33.

The whole is supported on legs 34 or in any desired way.

The impeller casing 7. is preferably of the same diameter throughout and the impeller is of nearly the same extent, allowing for the vanes 10, so that it does not strike said vanes, The convolutions of the impeller may be of any sha-pe or contour. The vanes 10 in the impeller casing and the vanes 5 in the basin 4 may be of any shape or contour desired or found practicable.

rllhe pulp or cellulose and the bleaching agent can be'placcdinto receptacle l in any desired manner, preferably through the mouth or opening 2, and when properly filled the shaft 23 is put in motion. This revolves or rotates the impeller 21 and thus the revolving impeller through its convoluted blades carries and forces the pulp upwardly through `the impeller casing 7, the pulp and bleaching agent passing up into t-he uptake and as the pulp passes up through the uptake 18, it reaches the mouth 19 of said uptake and is forced over the peripheral upper edge of said mouth and falls down by gravity through space 11 between the uptake'and the w'all of the receptacle or tank 1, dropping onto the bottom and into the basin 4, and between the vanes 5 thereof, filling the w-hole bottom.

It will be seen that the lower blade 4() of the impeller 21 extends below the impeller casing some distance. The revolving rotary motion given to the pulp by the impeller rotating would be transmitted to thc pulp mass, but it is impeded by the vanes 5 in the basin 4, and the mass of pulp and bleaching agent become a mass surging in vertical radial planes at the bottom of tank, and as the impeller continues to revolve and the heavy pulp continues to fall to the bottom, the mass has no avenue of escape, except by going up through the impeller casing and as it passes through said impeller casing. the vanes 10 in said casing again retard its tendency for rotation and impede it and again the pulp mixture must move upwardly in a straight line, which it tion.

does, passing up into the uptake 18 and out of the peripheral mouth thereof to again gravitate to the bottom to' again be re-forced upward-1y in a straight line.

The vanes 20 assist in keeping the pulp in a straight or vertical line of ascension, and inasmuch as air is forced through the air passage 12 up into the pocket 16 escapway until the bleaching action is completed and the bleach liquor exhausted in the batchA method, and in the continuous method, the pulp is carried into the other tanks when partially bleached, by means of av worm conveyor at the top of the tanks, or by any other method, not shown.

It will be' understood from the above description that the vanes 5 at the bottom of the tank prevent rotation of the stock in the bottom of the tank, and the vanes 10 in the impeller casing prevent the heavy pulp stock from assuming a rotating mo- The vanes 10 are pitched substantially perpendicular to the plane of the periphery of the impeller and are fastened to or cast integral with the impeller casing. They extend from the bottom of the impeller casing to the top thereof.

The extension of thevanes 10 above the impeller are pitched at an angle to the vertical, varying between 30 degrees and 8O degrees. depending on the pitch or lead of .the impeller and the speed at which the impeller travels, so that the reaction of the stock or pulp forced by the impeller strikes these vanes 10 and rebounds or reacts in a vertical direction. This agitation thoroughly mixes thepulp and bleaching agent.

It will be noticed from the drawing and it is a fact. that the impeller is raised ofi' from the floor or bottom of the bleaching `tank 1. and should be made as shown, and

that the bottom impeller blade should be placed above the extreme rbottom of thel bleaching tank.' However, I do not confine myself to the exact statements just set forth above as thc parts may bc varied to suit. particular case of pulp bleaching. i

It will be readily understood from the above. description that the re"olvingor rotating impeller has a tendency and does im-v part a rotary action to the pulp mass at the bottom of the tank or receptacle, however, I employ means for transfori'uing this rotary action and tendency and impart an upward vertical action to the pulp, negativing said rotary action. I also accomplish a more thorough and intimatemixture of the cellulose and bleaching agent thereby.

i It may be stated that I provide a method of forcing the pulp off of the impeller by y rotary force and against the impeding '10/ency towards hydration of the cellulose fibre, with a consequent loss in libre, but, due to my method and construction, this hydration is maintained at the lowest possible point.

In my method and apparatus I can handle and bleach pulp having a density of from 12 to 25%. but I do not claim this broadly as it has been done for many years,

but what I claim is my method and apparatus for handling the pulp and pulp liquor as herein described.

Instead of using a basin and vanes at the bottom as herein described, I may form and shape the bottom of the tank or cylinder itself, so thatl it Will do the work of the basin set forth herein.

It is perfectly obvious that changes and modifications may be made in mv invention without departing from'the spirit and principle thereof and I Iclaim all such modifications and changes which will fall within the scope of this specification and claims, which sets forth a preferred method .and means, the method and construction herein set forth being a preferred one.

What I claim as new and my inventiony and desire to secure'by Letters Patent is l. Inpulp bleaching, the method of moving a mass of pulp and bleaching agent by imparting to thebottom of said mass a slight initial' rota-ry movement, then impeding said rotary movement of the mass, and then transforming said rotary moving -mass into an upwardly vertical moving mass.

2. 'In pulp bleaching, the method of moving a mass of pulp and bleaching agent by imparting to the bottom of said mass a tendency to rotate, then impeding said mass in its tendency to rotate, and then` transforming said impeded mass into an upwardly vertical moving mass.

3. In pulp bleaching. the method of move ing a massbf pulp and bleaching agent by imparting' tofthe bottom of said mass a tendency to Arotate, then impeding said mass in its tendency to rotate, and then transforming said impeded mass into an upwardly vertical moving mass, then repeating said method until the pulp mass is partially or entirely bleached.

4. In pulp bleaching, an outer and an in- Iier cylinder spaced apart. means for mpving a pulp mass combined with bleaching 'agent up through the inner cylinder and allowing said pulp mass to fall over the top thereof and gravitate to the bottom of said outer cylinder, said means for moving said pulp mass upwardly in the inner cylinder being of a rotary character, means at the bottom of said outer cylinder for impeding any rotary action in the pulp mass and forcing it to move up vertically into the inner cylinder and means in the inner cylinder for impeding any rotary action therein of said pulp mass and forcing -said pulp mass through said inner cylinder in an upwardly vertical direction.

5. In, pulp bleaching a main tank, an

I?? inner uptake tank, arranged centrally with- .in said main tank, said uptake tank provided with anvimpeller screw and being widest at its top and spaced from the top of the outei tank, and a series of pulp mppding vanes atgthe bottom of the outer 6. In pulp bleaching, a main tank, anl inner uptake tank, arranged centrally within said main tank, said uptake tank provided with an impeller screw and being widest at its top and spaced from the top of the outer tank, a series of pulp impeding varies in the lower part of the inner uptake tank.

7. In pulp bleaching, a main tank, an inner uptake tank, arranged centrally within said main tank, said uptake tank provided with an impeller screw and being widest at its top and spaced from the top of the outer tank, a series of pulp impeding vanes Vat the bottom of the outer tank, and a series of pulp impeding varies in the lower part of the inner uptake tank.

8. In pulp bleaching, a main tank, circular 1n cross-section, contracting at its upper and lower ends but still retaining a circular form, an inner uptake tank circular, in cross-section arnanged centrally within said main tank` said uptake tank provided with an impeller screw and being widest at its top and spaced from the top of the outer tank, a series of pulp impeding vanes arranged in said tanks to prevent any rotary action of the pulp mass. l

9. In pulp bleaching, a main tank, an inner uptake tank circular in cross-section, arranged centrally within said main tank,

said luptake tank formed of an impeller casing and an uptake at the top thereof, said impeller casing provided with anximpeller screw and said uptake at the top of said impeller casting extending upwardly and widening until it reaches the widest extent forming .said impeded mass into an upwardly vertical moving mass, moving Said mass upwardly to a point and then allowing the same to gravitate downwardly and repeating said actions. A

l1. In pulp bleaching, ythe method of moving a mass of pulp and bleachingl agent by imparting 'to the bottom of said mass a,- tendency to rotate, then impeding said mass in its tendency to rotate and then transforming said impeding mass into an upwardly vertieal'moving mass, moving said mass upwardly to a point and then allowing the same to gravitate downwardly, and repeating said actions, applying a rotary force 'to said upwardly vertical moving mass, and at the same time reacting on the mass to keep said mass moving upwardly to provide a thorough mixture of' said mass and bleaching agent to prevent theforming of nodules.

'screw is operating.

i k12. In pulp bleaching, a main4 tank, an

inner uptake tank, arranged within said main tank and spaced therefrom, said uptake tank provided with an impeller screw pulp mass is forced when" the impeller screw is operating.

13. In pulp bleaching, a main tank, an inner uptake tank, arranged within.said main tank and spaced' therefrom, said uptake tank provided with an impeller screw, a series of pulp impeding vanes at the bot- 00m of said uptake tank, against which the pulp Amass is forced while the impeller In testimony whereof, I'affix my signa- .t-ure at Vatertown, New York, this twenty- 

